Safety plug



"Sept. 18,1928. 1,534,911

w. DAVIS SAFETY PLUG Filed July 26, 1926 1 Am w w WILLIAM DAVIS. lmvemon ja W A for/vey.

Fat-exited Sept. 18, 1928.

UNITED "STATES 1,684,911 PATENT OFFICE.

WILLIAM DAVIS, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-HALF TO ITALIAN- SWISS COLONY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

SAFETY PLUG.

Application filed July 26,

My invention relates to in'iprovemeliits in safety plugs, and more particularly to plugs adapted to be inserted in receptacles or containers containing liquids, and wherein the pressures of gases within the receptacle is automatically kept within a certain predetermined limit, and as soon as this limit of pressure within the container is exceeded, said plug will act to relieve the pressure within said container and permit it to drop.

Another object of my invention is to provide means in a plug of the kind described, whereby the passage of gas under pressure is permittechbut whereby the flow of liquid through the plug is obstructed and retarded. Another object of my invention is to provide means on a plug of the kind described, whereby the insertion of said plug into a container is limited, so that there is no danger of accidentally or carelessly driving the plug too far into the opening of the container and thereby shut oft the outlet end of the gas relief passage thereth'rough.

This invent-ionhas among its other objects, the production of a plug of the kind described, which shall be simple, safe and reliable in its action, sturdy in construction, and eiiicient and satisfactory for use wherever found applicable.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art to which this invention appertains, from the disclosures herein given.

To this end, my invention consists in the novel construction, arrangenii-ent and combination of parts herein shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts,

Figure 1 is a sectional View, showing the plug in operative position in the opening of a container; and

Figure 2 is a vertical elevation of the plug.

In the drawings, wherein I have illustrated the preferred embodiment of my invention, 3 indicates a receptacle or container of any desired size and shape, adapted particularly to contain liquids therein, the level of said liquid being indicated at 4:. At some suitable point in the container, as through its top wall 5 there is placed an opening 6, into which it is intended to insert my improved safety 1926 Serial No. 124,800.

plug to control the pressurev within the cont ainer.

Zlfhe plug comprises a body part, prefera-biy tapered toward its lower end as atT, so that the plug may be easily inserted within the preferably tapered opening 6 of the container. Intermediate the ends of the plug, the same is recessed to provide a groove or channel 8 adapted to receive an elastic band 9 for a purpose to be more clearly hereinafter described.

One or more radial passages 10 lead inwardlyfrom the periphery of the annular groove 8, and an axialor longitudinal passage 11, of somewhat larger bore than the passages 10,-lead upwardly from the lower end of the plug and communicate with the inner ends of the radial passages 10, as shown.

IV hen the plug is inserted in the position shown inthe drawings, with the lower end of the plug at a distance above the top of the liquid ievel within the container, the pressure within said container will be automatically taken care of, and relief of said pressure will be had whenever it exceeds a certain predetermined amount. .The band 9, which may be the ordinary rubber band of the desired size, and thickness or strength, normally seals the passage of gas through the passages 10 and 11, but as soon as the pressure within the container exceeds an amount suiiicient to overcome the tension of the band, this gas will flow through the passages, moving or lifting the band and escape into the atmosphere. It is obvious that as soon as the pressure drops to the normal amount, the band will contract or seat itself in the groove, again sealing the passage until the pressure again exceeds the predetermined amount.

It is essential that the outlet ends of the passages 10 be at a point where the gas may escape into the atmosphere, and therefore in order to insure that the plug will not be driven too far into the opening in the container, either intentionally or carelessly, I have provided a shoulder 12 intermediate the lower end of the plug. and the groove 8. hen driving the plug securely into place, this shoulder will be driven against the top surface of the wall 5 of the container and thereby limit further movement of the plug.

An ordinary nail 13 may be driven through the plug, as shown, in lieu of providing a shoulder lQ thereOn, or inaddition thereto, if preferred, this nail alsoacting tolimit the downward movement of the plug into the opening. In order to obstruct the flow of liquid through the passages of the plug, while permitting the flow of gas under pressure therethrough, I have provided a small sack 14, containing a quantity of small shot or similar suitable SOllCl particles 15, therein, and insert this sack into the mainaxialpassage 11 intermediate the ends of the latter. A screen lfimay be placed across the passage 11 above the shot, in order to limit the insertion of the latter and to prevent any clogging of the small passages 10.

The bag 14 may be tied intermediate its 7 ends as at 16 to retain the particles 15 in place and prevent their dropping into the liquid within the container 3, the lower end of said bag being tightly compacted within the bore 11 as shown at 17. I

From-the foregoing description it will be seen thatliquids can not be splashed or otherwise accidentally conducted through the passages 10 and 11, the container being shipped in the upright position shown and stored in the same position, the tightly compacted lower end of the bag, and the solid, massed particles 15 also obstructing anyflow of liquid out of the passages. However, when the pressure within the container exceeds the amount controlled by the strength of the rubber band, it will exert'suificient force to push this band aside or lift the same and such excess gas will escape into the atmosphere, the band automatically contracting again as soon as the pressure of the gas subsides or is relieved.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of-my invention;

- hence I do not wish to be understood as limiting myself to the exact form, construction, ar-

rangement and combination of parts herein riphery of said plug at a point above said con-4.

tainer, means in said opening of the plug to obstruct the flow of'liquid therethrough, a screen intermediate said last-mentioned means and the exterior end of said opening of the plug, and means exteriorly only of the sealing said passage ther'eat to prevent flow of gas therethrough except whenthepressure of said gas exceeds a predetermined amount.

2. A safety device comprising a plug adaptedto be inserted into the opening of a receptacle and project thereabove, a radial exterior end of said passage andnormally passage leading inwardly fromthe periphery at said projecting end of theplug, a-longitudinal opening leading from the inner end of said radial passage and opening at the lower 1y; sealing the outletend of the same, and means for obstructing the flow of liquid through said passage, comprising a plurality of solid partlcles, means for retaining said particles within said passageand filling the lower end of the passage. i

WILLIAM DAVIS.

end of said plug, anelastic band encircling said plug at said radial passage and normal 

